Yes I believe I do. I’m sure other as well will have some input as well. Last few times I’ve done heat treating over a hot coal pit or a heat gun I’ve thought to myself “why am I getting so much wrap around heat and concentrate heat build up on the back of my bows?” My theory is that the heat is reflecting or bouncing off the form and building or ramping up the heat on the back that may not be sitting tightly on the form due to character of the stave used. I did some experimenting with heat gun and an old roughed out bow that had lots of character in it and clamped it down to my form but cut a strip of insulation and placed it between the bow and the form.
An example of what I used like this.
Frost King Foil Backed Fiberglass Pipe Wrap, 3"x1"x25'
https://a.co/d/b81d2hMAnything similar I’m sure would work too. You could even just take regular rock wool or pink insulation and cut it into 2” wide strips by say 1” thick sections and lay this down with some double sided tape even. The basic idea is to prevent or mostly eliminate heat wrap around scorch on the back where you don’t want it. My initial test seem promising and will be doing this on my next batch of heat treatment bows.
